1. Field of the Invention
The present invention relates to a case for rolled objects formed by rolling various kinds of sheets.
2. Description of Related Art
When stored and/or transported, rolled objects may be vertically placed with their end faces contacting the mounting surface or horizontally placed with their circumferential surfaces contacting the mounting surface. In these cases, however, disadvantages such as deformation and damage may occur at the part contacting the mounting surface on account of an influence of the load, depending on the material of the sheet. In consideration of this problem, each of Japanese Unexamined Patent Publication No. 2001-180657, Japanese Unexamined Patent Publication No. 2003-252395, Japanese Unexamined Patent Publication No. 2004-90977, and Japanese Unexamined Patent Publication No. 2004-118110 recites a case which is arranged so that the core of a rolled object is arranged to jut from the respective end faces, this core is supported so that the rolled object is suspended in a horizontal position, and such a rolled object is enclosed by planar wall members. Since this case prevents the load from concentrating on a single part of the rolled object, the above-described problems hardly occur even when the rolled object is susceptible to the influence of the load.
However, in the conventional arrangements above, the side wall components covering the circumferential surface of the rolled object are planar. These side wall components are required to be sufficiently thick to achieve the strength with which deformation or buckling is hardly caused by an external force applied to the side wall components during storage or transportation. As a result, the weight and size of the case are increased. Such largeness and heaviness are disadvantageous for storing and transporting rolled objects. Cases are therefore desired to be lightweight and small but have the same degree of strength. In particular, rolled objects tend to be large and heavy these days, and the weight and size of a case must be significantly increased to achieve a strength level necessary for housing a large and heavy rolled object. Much attention has therefore been paid to the weight reduction and downsizing of cases for this reason.
The present invention was done to solve the problem above, and an object of the present invention is to provide a case which is at least lighter than a case constituted by planar wall members but has the same degree of strength as the case constituted by flat wall members.